The threat of a tsunami from a huge earthquake in the Indian Ocean tonight has probably passed, a Thai expert said.

There has been no report of any tremor or abnormal sea behaviour in the Bay of Bengal region due to tonight's quake which stuck Northern Sumatra region of Indonesia, the Director of Alipore Meteorological office K K Chakraborty said here.

He said the quake, which struck at 9:38 pm (IST), had its epicentre 2700 km away from the city.

People in Thailand's southern coastal areas can return home, as the threat of a tsunami has passed, a top meteorological official told Thai television.

"The department has just issued another announcement allowing people to return to their homes.

"Three hours after the earthquake, there is no sign of a tsunami in any of the country" said deputy director general of the meteorological department.